kdelibs splitting: April iteration

[Stephen Kelly]

Kevin Ottens wrote:

>> The reasons I don't think KPushButton needs to exist are:
>> [...]
> 
> Agreed with all of that.

I took this as concensus and have ported away from using its KGuiItem API. 

Although most of the rest of kdelibs doesn't use the rest of the KPushButton 
API, we can't just s/KPushButton/QPushButton/ because some classes return 
pointers to KPushButtons (eg KDialog), which are probably used like 
button(i)->setDelayedMenu() etc.

I'll have to find out why the delayed menu stuff exists at all.

Thanks,

Steve.